Very late in the day at a sunny Lansdowne Road a rumour, courtesy of the broadcaster BT, started up that if Bath could level the game and hang on to the final whistle they would go through to the Champions Cup semi-final on tries scored.

Very late in the day at a sunny Lansdowne Road a rumour, courtesy of the broadcaster BT, started up that if Bath could level the game and hang on to the final whistle they would go through to the Champions Cup semi-final on tries scored.

You can imagine the effect that had, and judging by the stress radiating through the crowd of 43,958, a fair few of them had heard it too. In fairness to BT they clarified it before the final whistle, but by then no one was listening. Not that it mattered.

Very few of us at the start of the campaign - and certainly not in this parish - predicted a semi-final in this competition for Leinster. It won't matter to them a whole lot that it came in those circumstances for they played like a team who believed they would win. Maybe that's that pedigree does for you, and in the premier competition in Europe Leinster have that.

Clearly they'll need it if that journey takes them to Marseilles to play Toulon, or to Brighton to face Wasps - the outcome of which we'll know this afternoon - but for the moment they will enjoy the achievement.

It came courtesy of a better set-piece, and penalty count that was so lopsided, 12-4 to Leinster, as to make you wonder if it was Bath or referee Jerome Garces who was off the mark. Certainly in that fraught endgame the home team got two favourable calls from the Frenchman, and they needed both.

By that point the home supporters were on the edge of their seats fearing the counter attacking of Anthony Watson at fullback for Bath. Operating off poor Leinster kicks, or poorly chased kicks - or both - he spread panic in the home ranks. 'Chaos' is the state Bath coach Mike Ford most enjoys: when the game unravels and his team can attack from anywhere.

Leinster enjoy more structure, and starting with their scrum they had a penalty platform, and in fairness to coach Matt O'Connor, they had a good menu to work off from set-piece, the most effective of which involved the excellent Sean Cronin using his searing pace.

The man in centre stage, however, was Ian Madigan. His right boot was inch-perfect from start to finish which earned him the man of the match award. Yet from a first 40 minutes where he was clearly in the groove he still managed one little sequence that was at the other end of the scale.

It started with an average clearing kick on 20 minutes, and then developed with a missed tackle on the receiver, Horacio Agulla. It was as if Madigan was reacting to the howl from the crowd when he decided to pile onto the heap that was the tackle on the Bath wing, leaving Leinster unguarded on the open side of the ruck - and sure enough scrumhalf Micky Young was through it like a scalded cat.

Leinster were baling water from there, and when George Ford came around the back of their stock-in-trade mini play off a ruck, he burned Devin Toner and then Rob Kearney to score. You wouldn't have blamed either Leinster man, and it was a clear warning of what the visitors could do in the right circumstance.

They couldn't help themselves, however, specifically with Watson carded on 26 minutes for contact with Kearney, who was in the air. His backside had hardly touched the bench when his team were giving away their fifth penalty of the game and Madigan planted it from just inside 40 metres.

It heralded the start of an awful period for Bath - conceding another penalty almost immediately to allow Leinster go to touch and get control, and then a readily avoidable knock-on by Young to surrender the ball again. Sure enough that retreating seven-man scrum gave Madigan another chance. You would have understood had Jamie Heaslip opted to ride the wave of momentum and go for the corner - instead he called for the tee and Madigan, with the aid of the upright, made it 12-5.

As if that wasn't enough, Bath managed to give him another shot before the break, this time against Stuart Hooper going offside at a lineout. Madigan was on the way back to the halfway line long before the ball had reached its target.

The Bath team stopped for their usual huddle before heading to the changing room. You can imagine what was said, and then the extras from Mike Ford, when they got inside. They had produced the best passage of attacking rugby to give us the only try of the half, but thereafter they were tuned into a different frequency.

Seven minutes into the second half, however, they got it bang on when Ford isolated Cian Healy and then fed Hooper for a try which left just three in it. That transformed the mood in the crowd, and despite another Madigan strike, on 51 minutes, they never settled until the final whistle.

The sight of Fergus McFadden going off concussed didn't help, but mostly it was the prospect of what the away team would do if they got the ball in broken play. Fortunately for Leinster, Bath couldn't quite get those planets aligned. Leinster are back in familiar territory, and mightily relieved to be there.